New Telephoto vs. Telephoto Extender

[Thlayle]

I am an amateur photog with some good gear, currently shooting with a Canon 5DMk4 and I have Canon's EF 70-200mm f/2.8L IS III USM lens. I love both.

I find that 200mm is a bit minimal for my purposes when doing some bird photography. I could switch to my crop sensor, Canon T2i, but it is of course not nearly as fun to shoot as the full frame and is missing some of the current features of newer Canon cameras. And that would take me, if I understand this correctly, to approximately 300 mm equivalent focal length. Having done this at times, I still am wishing for more focal length.

This brings me to the idea of a Canon 2x extender for the telephoto I have. That will take me to 400 mm on my full frame, but the cost is just about 1/2 of the current pricing on a Sigma 150-600 5-6.3 "contemporary" or similar choice.

So my question(s):

Are extenders, this one specifically, worthwhile? Do they perform well enough?

I am doubting 400 mm will look much different to me in terms of magnification than the 200mm on my crop sensor camera; correct?

And as for the Sigma and Tamron 150 to 600 lenses, is it possible to say if there's enough boost in focal length and performance for the extra cost?

It seems to me that the lenses I have been looking at, get extremely pricey beyond this. The fixed focal length telephotos above 400 mm that I have seen are also above my budget, getting into prices around $6,000 and much higher. So: I am pretty sure my search considerations are for telephoto zooms with higher aperture values.

I realize there's lots of variables to consider here and that much of this comes down to personal preferences (including budgetary ones). Still, if you have any advice to share, I will appreciate it.

Final note: I just did the math, considering the 200mm lens with the 2x extender on my crop frame and that would take me to over 600mm. So there's that.

Regards and thanks,

Randy

[Manfred M]

Nothing is quite that simple, otherwise the lens makers would be selling a lot more teleconverters than long lenses.

A 2x teleconverter loses 2 stops versus the nominal rating of your lens, so your f/2.8 is now down to an f/5.6 lens. Add to that the optical degradation from using a teleconverter (mainly distortion and additional aberrations) and you can see why most photographers use them sparingly. Another factor will be your camera's autofocus capabilities; most are limited to somewhere between f/5.6 and f/8 (at your maximum aperture) before autofocus becomes unreliable. Most credible sources suggest staying with a 1.4x telecoverter to maximize image quality.

Your math is off a touch too. Your full frame camera versus a Canon crop frame has a 1.6 crop factor, so your 200mm lens will perform as a 320mm lens, not 400mm on a crop sensor Canon.

The final factor to consider is that serious birders (like sports photographers) tend to have the most expensive gear. Fast glass and top of the line cameras is best because birders tend to high-ISO, fairly wide open and in burst mode to capture birds in flight.

[LenR]

There are disadvantages to using extenders as Manfred points out.
See the attached which may help.

https://www.photoreview.com.au/tips/...tender-lenses/

[rpcrowe]

Although it is fairly pricey, the Canon 100-400mm f/4.5-5.6L IS ii is an excellent BIF lens.

However, we generally shoot birds with our zoom lenses cranked out to the maximum focal length. Canon shooters are quite fortunate to have an excellent prime BIF lens that is both relatively lightweight and less expensive than the long 100-400mm zoom.

The Canon 400mm f/5.6L is one of the best BIF lenses out there and is only available for Canon EF mounts. Since this lens has been produced for many years, photographers often have the opportunity to purchase a used copy at a very decent price. It is a very sharp lens with exceptional AF on the right camera like the 7D Mk2. No IS but, I always shot BIF at high shutter speeds which negated the need for IS...

eBay has these lenses used, priced from the mid-six hundred U.S. Dollar range.

https://www.ebay.com/sch/i.html?_fro...ete=1&_fosrp=1

I agree that 400mm on a full frame camera is at the absolute minimum end of the focal range you need for BIF. I had used the 400mm f/5.6L lens for years (until I switched to Sony) and especially loved it with a Canon 7D Mark-2... It is a shame that other companies do not produce a prime like this one... The 7D Mark2 is an exceptionally good action camera and the combination of 400mm f/5.6L lens with the 1.6x Canon crop factor for their APSC cameras results in a 640mm equivalent focal length...

I also occasionally used a 300mm f/4L IS lens on the 7D2 which resulted in an equivalent 480mm f/4... Not the greatest focal length but decent and IMO better than using a TC to increase the FL. BTW: I have used the 300mm f/4L IS lens on a 7D (before I owned the 7D2) with a 1.4x TC. This resulted in an equivalent 672mm f/5.6 lens... Decent IQ and AF with the combination but, not equal to the lenses without the TC...

[DanK]

I agree with Manfred about the disadvantages of a TC. I have a 1.4x TC, but I don't use it instead of a longer FL. I use it if I don't want to lug the considerable weight of a longer lens but think that my 70-200 might end up a little short.

Re the Canon 100-400 f.4.5-5.6 L: I have one, and it is a superb lens, but I don't think it's very good for birding. I don't do much birding, but when I do, I find 400mm to be too short some of the time. (In fact, I sometimes end up throwing on my TC, despite its drawbacks). It's also very expensive.

If I were serious about birding, I would look very seriously at the three Sigma and Tamron 150-600mm competitors:

Tamron G2, currently $1200, usually $1400, compared with $2400 for the Canon.
Sigma Contemporary, now $900, usually $1100.
Sigma Sport, not $1850 ,usually $2000.

The Sport is a better lens than the contemporary, but in addition to being more expensive, it's much heavier than the others. I'd suggest checking out reviews of these.

[Chataignier]

I'm no longer a Canon shooter (gone to Fuji) but in my Canon days I used the sigma 150-600 quite a bit and found it excellent, though a bit tiring to use because of the weight. These too can be bought for modest sums used.
Personally I would much prefer even a used 150-600 to a shorter lens with an extender.

[Geoff F]

I also use a Sigma 150-600 lens. The sport version. My thinking was that model is a bit better construction and weatherproofing so when shooting wildlife there is a fair chance that I will knock my lens and get caught in some showers. So although the cost is higher it might be a good additional investment.

Works OK and is quite sharp at 600 although your focus depth is rather shallow at that length.

Potential problems with a x2 extender have already been mentioned; but also remember that they won't physically fit onto all lenses. So check before purchase.

I frequently use a 1.4x on my macro lens but have to add in a 12 mm extension tube to make the extender/lens connection. That loses the ability to focus at infinity.

Regarding the large lens weight factor. When photographing birds I usually use a tripod with a ball head which is lightly adjusted so I can still swing around to follow a moving subject but the tripod takes the weight strain.

A 600 lens or a 400 plus a 1.4x extender is a difficult choice. Are there any test results available?

[Thlayle]

Thanks -- all very helpful comments. I have not thought of this a simple comparison. I realized from the start that there's trade-offs involved. I am getting the idea that the extender is probably not the way to go. I knew about the lost stops, but for what I am willing to spend on an added telephoto lens for birding, anything I would choose automatically would not have anything like t 2.8 lens I now have. The lost image quality is more of concern.

I cannot claim to be a serious birder, or bird photographer. By the way, in my opinion the good bird photographer really should be a good birder first. That to me seems to be the key to getting good bird shots.

Nonetheless, my interest in this is serious enough to consider a lens like the Sigma or Tamron 150-600 lenses, and yes as a rule I would expect to be shooting with it almost always cranked out to the maximum focal length. And from what I have seen in these lenses and pricing, it's only the zoom telephotos that will actually fit my price range I am considering. (Oh, and Manfred, your point about my math is well taken, but I was just shooting from the hip, not quite remembering the 1.5 vs 1.6 crop factors.)

I have been very interested in the Canon 100-400, but I am thinking I will still want to reach further than the 400mm.

So in total, this input seems to point me away from an extender to a different telephoto for some of my birding endeavors.

David and Geoff: thanks for your comments about the Sigma Sport and Contemporary. I like the idea of the lighter weight of the Contemporary but the weather sealing of the Sport might actually be more important/useful to me.

Last note: (I almost hate to mention this, especially given my limited knowledge base on the subject) but...isn't a TC (teleconverter) a different piece of equipment than an extender, and then of course the extension tubes a yet another thing?

Again, thanks to all.

[Tronhard]

Hi Randy:

I just came across this thread. I tend to shoot mostly on the long telephoto end as my subjects are usually wildlife and, being in NZ, that is likely to be birds.

I have a lot of Canon lenses and also both the 1.4 and 2.0x teleconverters (they are synonymous with extenders). As has been pointed out there is definitely a loss of speed with the use of teleconverters, and many bodies don't work with them as regards autofocus and auto*exposure. Since you have the 5DIV you should be able to auto-expose with one and I have had some good results - although I was using the 7DMkII, which being a crop sensor gave me a FoV advantage over the FF sensor of the 5DIV.

I personally would also recommend the Sigma 150-600 C (contemporary lense). I have one, and find it excellent to use. It is significantly lighter and cheaper than the sports version - I don't have that but I DO have the 60-600 S, which is an awesome unit if you need he range of focal lengths, but as heavy as as howitzer! I do weight-training classes so I can handle the gear.

If you want to get "closer", then I would consider getting a 7DII body - they should be more available as people move to MILCs - the 90D is newer and has a bigger MP count, but the tracking is not as good as the 7DII, which is still the best in the DSLR Canon Range. The advantage is given by the crop sensor's narrower FoV, meaning you get one equivalent to a FF sensor with a 1.6x greater focal length. Obviously, you could crop your full frame image, but the pixel density to get to the same FoV reduces by a factor of about 2.56. I shoot with the combination of crop sensor 150-600mm lens and that gives me a FoV of up to about 240-960mm, which is pretty decent and without the disadvantages of the teleconverter.

I have found a photo taken with the 5DIV and the Sigma 150-600 C. I thought it might give you a sense of coverage and quality of the combination of the two, FWIW.

The first is the full frame image (downsized to publish) of a wind-surfer who was about 400m away - hand-held. The day was extremely blustery and a lot of salt in the air.

The second is a crop of the same image:

[Thlayle]

Thanks, Trev. Great info there that really helps. Your reference to the "howitzer" weight will stay with me as I continue to look at the choices. I should really consider the weight factor since my camera, usually with battery pack) is heavy enough already.

Acquiring another camera once would have been off the table for me previously, but nowadays I might give that some scrutiny. It does seem like more DLSR models may be popping up in the used market. Your crop v. full frame examples really show the possibilities of going that direction. As much as I have loved using my T2i, and I have used it extensively since buying it 10 years ago, I am finding I don't pick it up much anymore. I'm not sure what that tells me about getting a newer crop sensor camera, but still the idea has some appeal.

Regards,

Randy

[DanK]

Trev's point is important. The impact depends on the cameras because the practical impact depends on both the crop factor and pixel counts. Here are the numbers for the 5D IV and 7D II, if my arithmetic is right.

In Canon cameras, full frame sensors are approximately 1.6 times the length of crop sensor cameras in each direction, so the area of the FF sensor is approximately 1.6^2 the area of the crop sensor. It's not exactly that, but close. The area of your 5D sensor is about 2.57 times the area of the 7D II sensor.

Your camera has 30.2 MP. The 7D II has 22.4 MP. that is, your camera has about 1.49 times the number of pixels as are on the 7D II sensor.

The ratio of those ratios is about 0.58. So, your camera has 58% as many pixels per square mm as the 7DII.

It's this ratio, rather than the simple 1.6 or 1/1.6, that is most relevant for this discussion. If you crop your 5D IV images to get the framing you would get with the 7D II and the same lens, you would have 58% as many pixels on the subject as you would have had with the 7D II.

However, this isn't the only consideration. I have the original 7D, which has an 18 MP sensor that is in other respects inferior to the 7 D II and certainly inferior to the 5D IV. So I get 65% as many pixels when I use my 5D IV, and I get all the other benefits. If I'm gong to do other types of photography on the same outing, I often take the 5D IV and a TC, accepting the lower quality on the longest shots in return for other benefits

[rpcrowe]

Larger birds photographed in areas in which you can get fairly close to the birds, can be photographed with less sophisticated equipment. I shot these sand hill cranes, years ago, at the Bosque del Apache Wildlife Refuge, South of Albuquerque, New Mexico using a Canon 40D and the 300mm f/4L IS lens, which resulted in an equivalent 480mm focal length...



The Bosque is the best area in which I have ever shot BIF...

[billtils]

I agree with Manfred about the disadvantages of a TC.
...
Tamron G2, currently $1200, usually $1400, compared with $2400 for the Canon.

A couple of comments:

Yes, you lose up to a stop if you fit a 2.0 TC but that is not the same as saying you lose IQ with any TC. Been shooting pretty well nothing but the Nikon 300mm PF with Nikon 1.4TCII for well over a year now and the combo works very well - I can't see any loss of IQ in the combo to what I get from the naked 300, which backs up Manfred's comment. The 300 + 1.4TC + DX body gives an EFL of 630mm which is good enough for most occasions. (The f8 autofocus situation is a non-event with this rig).

As far as the 150-600s go, I had the Tamron but the 300 combo leaves it trailing for IQ (Before I dumped it I reviewed the EFL of shots in my library and most were taken in the high 300 to mid 400 range - it may be worthwhile looking at where yours fall). Add the weight penalty and the change was the best thing I ever did for wildlife photography.

Oh, and it was initiated by feedback from members right here on CIC .

You can see some examples on this fairly recent thread Seal and puffins

One last comment - the whole "TC" thing started for me at a time when I was shooting FF (Nikon D810) and was very much initiated due to the weight burden. I recently added a D500 crop body to my bag of goodies for the its vastly superior burst rate but the overall quality of images is high enough that the D810 is now on a shelf to be used only where it has something specific to offer, such as low-light performance.

[DanK]

Manfred referred to image degradation when using TCs. That’s been my experience as well, but the degradation with my 1.4 TC modest enough that I’ll use it in a pinch.

If you’re not going to print moderately large, the degradation from a good 1.4 x TC may be inconsequential. It depends on the equipment.

The loss of light is one stop from a 1.4x TC and 2 stops from a 2x TC.


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[rpcrowe]

The degradation of IQ and AF from a TC depends on the quality of the original bare lens and with the quality of the TC added to the lens.

The better quality lenses matched with appropriate teleconverters will often provide VG to EX image quality. As I mentioned earlier, my experience using a 1.4x TC has mainly been mostly with the Canon 300mm f/4L IS but, I have also used this TC with the Canon 70-200mm f/4L IS - both lenses provided quite decent IQ with no perceptible decrease of AF functioning. I used 1.4x teleconverters with the Canon 100-400mm f/4.5-5.6L IS Mark-2 lens and found that the AF of the TC mark-3 TC was a bit more snappy than that with the TC Mark-2.

I have never used a 2x TC but, have read some very encouraging reports of the 2x combined with the 70-200mm f/2.8L IS Mark-3 lens...

However, IMO, a TC is good for occasional use when the decreased weight (compared with the weight of an individual longer FL lens) will make up for any decreased performance. However, I would not want to use a lens + TC combination for long term and serious photography.

[Donald]

Re the point of image degradation if using a 1.4x or 2x tele-converter, I would defy anyone viewing a print of, say, 20" x 16" in a normal way, to say whether a tele-converter was used or not. Fine if your one of those pixel peepers who stand about 2 inches from the print and look for problems, you'll maybe see a difference. But if you are a normal person looking at the print in a normal way, then I'd suggest your not going to be able to tell.

[DanK]

Re the point of image degradation if using a 1.4x or 2x tele-converter, I would defy anyone viewing a print of, say, 20" x 16" in a normal way, to say whether a tele-converter was used or not. Fine if your one of those pixel peepers who stand about 2 inches from the print and look for problems, you'll maybe see a difference. But if you are a normal person looking at the print in a normal way, then I'd suggest your not going to be able to tell.

Regardless of the power of the TC, the brand, or the model?

https://www.imaging-resource.com/art...y-a-comparison

By the same token, its true that many people, if not looking closely, may not notice the difference between images created using budget and high-end lenses, but that doesn't imply in my mind that we should all just buy cheap gear.

[xpatUSA]

By the same token, its true that many people, if not looking closely, may not notice the difference between images created using budget and high-end lenses, but that doesn't imply in my mind that we should all just buy cheap gear.

Interesting point, Dan. A corollary is that my very low-MP Sigma DSLR shows little difference between images shot with an old 24-70mm zoom and a much higher quality 17-50mm lens, abberation-wise.

[billtils]

Re the point of image degradation if using a 1.4x or 2x tele-converter, I would defy anyone viewing a print of, say, 20" x 16" in a normal way, to say whether a tele-converter was used or not. ... But if you are a normal person looking at the print in a normal way, then I'd suggest your not going to be able to tell.

This (hopefully) normal person agrees.

[Manfred M]

This (hopefully) normal person agrees.

The "normal person" often thinks a selfie done on a cell phone is a good image...